干热岩储层水力压裂改造的电磁法监测评价研究进展

从岩石受压破裂过程电阻率特性、裂缝型岩石电阻率特性、岩石电阻率与渗透率关系3个方面出发，总结了电磁法水力压裂监测评价相关的岩石物性基础研究，介绍了干热岩水力压裂现场电磁法监测应用案例。基于岩石电性基础研究总结得出：岩石在受压破裂过程中会伴随着显著的电阻率变化，且电阻率变化特征与岩石中的含水饱和度紧密相关；裂缝数量、宽度与粗糙度等都会对岩石的电阻率产生影响，影响趋势与裂缝是否含水有关；可通过修正Archie定律与Kozeny-Carman模型建立特定岩石的电阻率与渗透率关系模型。讨论了电磁法应用干热岩水力压裂监测评价所面临的难点，包括：（1）研究高温高压条件裂缝型致密岩石的电阻率性质；（2）研究高温高压条件裂缝型致密岩石渗透率与电阻率关系模型；（3）研究开发具有更高精度、更小分辨率、更强抗干扰能力及更远探测距离的电磁法探测新理论新方法、新技术新装备。

Research progress of electromagnetic monitoring and evaluation of hot dry rock hydraulic fracturing reservoir

The development of the hot dry rock is one of the important ways to achieve the goal of "double carbon". In the context of monitoring the hot dry rock reservoir with the electromagnetic method and establishing a scientific and efficient hot dry rock reservoir evaluation system, this paper reviews the basic researches of the rock physical properties related to the electromagnetic hydraulic fracturing monitoring and evaluation, focusing on three aspects, namely, the electrical resistivity characteristics of the rock in the process of fracturing under pressure, the electrical resistivity characteristics of the fractured rock, and the relationship between the rock electrical resistivity and permeability. The application cases of the electromagnetic monitoring in the field of the hot dry rock hydraulic fracturing are introduced. Based on the basic researches of the rock electrical properties, it is concluded that:the pressure fracturing will be accompanied by significant electrical resistivity changes of the rock, and the characteristics of the electrical resistivity changes are closely related to the water saturation in the rock; the number, the width and the roughness of the fractures will affect the electrical resistivity of the rocks, and the influence trend is related to whether the fractures contain the water; the relationship between the electrical resistivity and permeability of specific rocks can be established by modifying the Archie's law and the Kozeny-Carman model. Finally, the tasks faced by the application of the electromagnetic method to the monitoring and the evaluation of the hot dry rock hydraulic fracturing are discussed, including:(1) the study of electrical resistivity properties of the fractured compact rocks under high temperature and high pressure; (2) the relationship model between the permeability and the electrical resistivity of the fractured compact rock under high temperature and high pressure; (3) new theories, new methods, new technologies and new equipment of electromagnetic method detection with higher accuracy, finer resolution, better anti-interference ability and longer detection distance.